U.S. Pat. Nos. 5,013,806; 5,071,930; 5,071,931; and 5,071,932 (issued to Blevins and Turner in 1991) disclose copolymers of 3,4-epoxy-1-butenes and maleic anhydrides. Other than the compounds and processes described in these patents, no other known reference discloses copolymers of 3,4-epoxy-1-butene with maleic anhydride or its derivatives. While the copolymers of Blevins and Turner are useful, it would be desirable to have copolymers that are more resistant to moisture and hydrolysis.